Method and Apparatus for Decreasing the Time Required to Generate a Channel Map in a Television Signal Receiver
The present invention relates to the field of television. Specifically, the present invention relates to the field of creating a channel map for a television signal receiver, such as a television set, set-top terminal, video cassette recorder, etc. More specifically, the present invention relates to the field of decreasing the time required to generate the channel map of receivable channels for a television signal receiver.
When a user purchases a new television set or moves to a new location, his or her television set must create a channel map of the channels currently receivable by the television set. In other words, all the available frequencies at which television channels could be broadcast must be checked to determine where the channels available to the television set are. This is true whether the incoming television signal is from a terrestrial (over-the-air) broadcast or comes from a cable television network.
The television then stores in memory the location of the available channels as a channel map. Most modern television sets can automatically create a channel map by scanning through the available channel frequencies and noting at which an intelligible signal is received. Additionally, most modern televisions allow the user to manually add or delete channels from the channel map to optimize the map""s conformance to the viewer""s channel preferences. Channel maps may also be created by other devices which act as television signal receivers, for example, video cassette recorders (VCRs), set-top boxes or PC card tuners.
After the channel map is created, it is used to tune the available channels for the user. For example, when watching television, viewers typically desire to flip through the available channels to see what is being broadcast. This does not require the user to consult a television programming guide or enter a specific channel using, for example, the ten-key keypad on a remote control unit.
Surfing sequentially through the available channels is done by pressing a button on a remote control unit or on the television set itself indicating a desire to move up or down through the available channels. If, for example, the television set had been tuned to channel 4 and the user signals the television set to tune the next highest channel, the television set will consult its channel map.
The next highest receivable channel may be, for example, channel 8. Consequently, the television set skips directly from channel 4 to 8 without going to channel 5 where no broadcast is available. Thus, the channel map saves the user from successively tuning through each of channels 5, 6 and 7, where no broadcasts are available every time the user goes from channel 4 to channel 8.
If the user only receives terrestrial broadcasts of television signals, there will likely be many possible channels (or frequencies) at which no broadcast is being made, particularly if the user lives in a relatively remote area. On the other hand, if the user receives cable television signals, there may be premium, scrambled channels to which the user does not subscribe as well as available channels on which no broadcast is being made. Consequently, the user will, in any case, want the channel map to list only those channels that are clearly receivable, not those that are scrambled or only poorly received due, for example, to interference or distance.
As noted above, a channel map must be created whenever a new television set is brought into service or whenever a television set is moved to a new location where a different selection of television channels are available. Additionally, a new channel map must be created by a television set whenever there is, for any reason, a change in the selection of available television channels. For example, if a television user newly subscribes to a cable television system after using only terrestrially broadcast signals, or if a channel is added to, or dropped from, a cable network or commences or ceases over-the-air terrestrial broadcasting.
While channel maps are very useful to a viewer and make operation of the television set more efficient, channel maps also require time to create. The recent trend, particularly in cable television systems, is to provide viewers with 120 or more available channels. The amount of time and effort required to create an accurate channel map increases proportionally with the number of available channels. This situation will be further aggravated by the advent of both over-the-air and cable channels broadcast in the digital format. Using digital signals, a service provider can provide a greater number of available television channels.
Due to the more complex nature of the reception and demodulation of digital signals, the time required to automatically create a channel map increases even more.
While a channel map is being created, the user conventionally cannot tune any particular channel and watch the television. Consequently, there is a need in the art for a method and apparatus that minimize the time required to generate a channel map.
It is an object of the present invention to meet the above-described needs and others. Specifically, it is an object of the present invention to provide a method and apparatus that minimizes the time required for a television signal receiver to create a channel map of the available channels.
Additional objects, advantages and novel features of the invention will be set forth in the description which follows or may be learned by those skilled in the art through reading these materials or practicing the invention. The objects and advantages of the invention may be achieved through the means recited in the attached claims.
To achieve these stated and other objects, the present invention may be embodied and described as a method of minimizing the time required to generate a channel map for a television signal receiver that has at least two tuners. The method of the present invention is accomplished by simultaneously using both tuners in parallel to scan for receivable channels to be listed in the channel map. The method concludes by generating a unified channel map based on the output from the two or more tuners scanning for receivable channels.
The method of the present invention can be made more efficient by exploiting the characteristics of the available tuners. For example, if one of the tuners is a digital tuner and another of the tuners is an NTSC tuner, the method preferably includes scanning for receivable channels with the NTSC tuner beginning at a lowest possible channel allocation. Accordingly, scanning for receivable channels with the digital tuner is begun at the highest possible or highest commonly used channel allocation.
The method also is made more efficient by identifying a type of signal source of an incoming television signal or signals, i.e., terrestrial, cable etc. The channel mapping is then performed in accordance with the identified type of signal source of the incoming television signal or signals. There are at least two means of performing this identification, for example, (1) displaying a menu requesting user input identifying the type of signal source of the incoming signal or signals, or (2) testing the channel allocation configuration of the incoming television signal or signals.
The present invention also encompasses the apparatus required for executing the foregoing method. For example, an apparatus according to the present invention minimizes the time required to generate a channel map for a television signal receiver and may include a processor; a first tuner; a second tuner; and at least one input for a television signal. The processor controls the tuners in parallel such that both tuners simultaneously scan for receivable channels to be listed in the channel map. More than two tuners can be included.